Species of the Month August 2024
Roesel's Bush-cricket (Roeseliana roeselii)
During 2024, our 20th anniversary year, we are revisiting our Species of the Month archive to reshare some of our "greatest hits" through the years. This month we are going back just a couple of years to August 2022, and the lovely Roesel's Bush-cricket. It has now been ten years since the species first arrived in Wales, and it seems to be increasing exponentially. Records in the SEWBReC area have almost doubled in the last two years, from 98 to 180. It would be particularly good to fill in the 10km gaps in distribution, shown on Aderyn here.
Roesel's Bush-cricket is a robust medium-sized species of dark green / brown. It has a distinctive bright green "collar", a c shaped mark as viewed from the side. The species first arrived in Wales in 2014, and has been spreading west and north, reaching Anglesey in 2019. It is usually short winged (shown in the picture, right), but a long winged form occurs, particularly during hot summers. The long winged form is likely to spread more easily, so this species is particularly influenced by climate change.
The call of Roesel's Bush-cricket is very distinctive, a loud buzz which has been likened to overhead electricity lines. It is audible to many people, but can be easier to hear using a bat detector turned to the lowest frequency. The call can be the easiest way to record the species, as individuals can be hard to track down in their preferred dense vegetation. The species used to favour salt marshes and dune systems, but now can be found on brownfield sites, verges and rough grassland.
The species could potentially be confused with Grey Bush-cricket and Dark Bush-cricket which are both a similar shape. However, both are duller coloured species, without the bright collar, and have very quiet calls.
You can find more identification information for Roesel's Bush-cricket on the Grasshopper Recording Scheme website, sound recordings of their call on Xeno-canto, and additional photographs on Steven Falk's Flickr.
Roesel's Bush-cricket are popping up throughout south east Wales, but we only hold 98 records at SEWBReC; you can view the 1km distribution for SEWBReC here and the 10km Wales wide distribution here.
If you spot a Roesel's Bush-cricket during August (or at any other time of year), please send us the record, ideally via SEWBReCORD or the LERC Wales App. Instructions on how to submit records are available here.
